1. Field of the Invention
This invention in general relates to the field of leads for the electrical stimulation of living tissue, and more particularly concerns a method of making a lead having a lobed lead anchor that permits large numbers of high quality leads to be produced in relatively short periods of time.
2. Description of the Prior Art
Electrical stimulation of the body is an increasingly important medical procedure. In this medical context the stimulating lead comprises a conductor covered by a pliable insulating material which is resistant to body fluids and an exposed electrode electrically connected to the conductor. Often the lead includes a means for anchoring the electrode and the lead in the tissue to be stimulated. One type of such a lead anchor comprises semicircular lobes formed in or attached to the lead body.
U.S. patent application Ser. No. 926,100 filed July 19, 1978 now U.S. Pat. No. 4,374,527 issued Feb. 22, 1983 on an invention of a Alfred A. Iverson, U.S. Pat. No. 4,154,247 on a invention of Edward G. O'Neill, U.S. Pat. No. 3,866,615 on an invention of John R. Henson, and U.S. Pat. No. 4,285,347 on an invention of Stanley R. Hess all disclose lobed lead anchors. The lobes in these prior art leads are formed either by injection molding, or as in U.S. Pat. No. 4,154,247 by heating the lead in boiling water and forming the lobe by hand. The injection molding method is quite slow and expensive, since the number of lead achors that can be made is limited by the number of molds available, and each mold must be assembled, filled, allowed to cool and then disassembled. The hand molding method, while being somewhat faster and cheaper does not lend itself to reproducability and high quality. Thus, a method of manufacture that would permit leads of the quality and reproducabilty obtainable with the injection molding method to be produced with speed and simplicity of the hand molding method.